Air Conditioning/Cooling/Refrigeration systems (hereinafter "refrigeration systems" or "cooling systems"), which utilize compressors, are least efficient when starting up. Prior to reaching optimum running conditions, the average net BTU output of the refrigeration system is below its rated capacity. The optimum run conditions of a refrigeration system are not obtained until all of the component parts of the system have obtained their design operational temperatures. This can take considerable time after the compressor starts because the thermal inertia of each device, which was just off and is relatively hotter than when running, must be overcome. Some of the component parts of a refrigeration system are:
a) Compressor PA1 b) Coolant-media (usually refrigerant gas). PA1 c) heat-exchangers: PA1 d) Coolant-media piping. PA1 e) Items within the controlled space which have thermal mass and inertia. PA1 a) The worst case scenarios (design-loads) that the systems are expected to encounter. PA1 b) Anticipated future expansions. PA1 c) Expected degradation of the system output due to aging. PA1 A) Reduce the electrical consumption of cooling/refrigeration systems by the modification of compressor run cycles. PA1 B) Provide compressor anti-short-cycling control to enhance compressor life expectancy and to further reduce electric consumption.
the evaporator (the heat-exchanger used to absorb heat from the area to be cooled and transfer that heat to the coolant-media); and PA2 the Condenser, the heat-exchanger used to release heat from the coolant-media to the external ambient environment.
The invention increases the net BTU output of the refrigeration system by cycle control of the compressor. By intelligently increasing the delay between compressor run cycles, (the amount of which has been experimentally proven and to be within reasonable limits) longer more efficient (higher net BTU) output cycles are generated.
In connection with refrigeration systems, it is common knowledge that the output capacities of cooling systems are usually determined by:
Anytime the demand on the cooling system is less than the cooling capacity, the cooling system is over-sized. This "over-sizing" condition exists, within a typical properly designed system, about 85% of the time and causes the cooling system to cycle the compressor in an inefficient and energy consuming fashion.
There is another system scenario that the invention also addresses; that is one where the compressor is undersized and never shuts off. While it would seem that there is no way to save energy, other than to shut the compressor off, the invention does just that. After a predetermined amount of continuous run-time the compressor is stopped for a predetermined amount of time and then restarted. While it would appear to one skilled in the art that this would cause temperature fluctuations, in fact, experimentation with the present invention shows that it has less of an effect than that of a door being opened for that duration of time. The thermal inertia and thermal storage of the items within the controlled space are used, indirectly, as a capacitor of sorts to absorb these thermal transitions and they do just that.
It has also been proven experimentally that while extending the compressor off-time and subsequent lengthening of the on-time increases efficiency, there are certain limitations that the inventor feels must be addressed. In a properly sized refrigeration system (one that is cycling), extending the off-time beyond certain limits will cause temperature fluctuations and also will serve no useful purpose as far as energy reduction. Subsequently, the invention will not allow the extended off-time function to have any effect when the compressor has been off for longer than a predetermined time.